Rodents generally cause chronic preharvest losses of 5–10% in rice and, in some regions, the problem is escalating (Singleton 2003). Impacts of pests on smallholder rice farmers also have important social and environmental dimensions (Heong 1999). Farmers often use inappropriate methods in their desperate attempts to reduce the impacts of rodents. This includes the use of broad-spectrum poisons such as endosulfans, organophosphates, and carbamates. Occasionally, these are mixed with used engine oil before applying them to flooded rice crops (Sudarmaji et al 2003). These chemicals and their inappropriate use are of major environmental concern. Another management action is the use of power mains to electrocute rats in flooded rice fields. This has led to deaths of people in the Philippines and Vietnam and therefore has major social implications.
Since 1996, there has been a concerted effort in Southeast Asia to develop an integrated package of ecologically based methods to manage rodent pests in lowland irrigated rice agroecosystems. This led to the development of village-level studies in West Java, Indonesia (Cilamaya; 1999-2002), and in the Red River (Vinh Phuc; 2000-02) and Mekong River deltas in Vietnam (Tien Giang and Soc Trang; 2001-02). We assessed whether these integrated practices lessened the impact of rats economically and environmentally and whether the involvement of smallholder farmers in the study influenced their perceptions and practices of rodent management. This paper reports on one element of this study: the use of chemicals, plastic exclusion barriers, and electrocution by individual farmers after they had participated in a community based program of integrated rodent management.